Grouting system



Feb. 15, 1944. R, L, A| `|N l 2,341,518

' GROUTIN'G SYSTEM Filed June 29, 1940 s sheets-sheet 1 INVENTOR.

Feb. 15, 1944.

` R. L. ALLIN GROUTING SYSTEM Filed Jun 29, 1940 3 Sheets-Sheet. 2

Feb. 15, 1944. R. L. ALLIN GROUTING SYSTEM Filed Jude 29, 1940` PatentedFeb. 15, 1944 UNITED STATES f PATENT OFFICE GROUTING SYSTEM RayL. Allin,.San Francisco, Calif;y Application June zo, 1940, serai No. 343,100

s'olaims. (c1.4 fz-eide) My invention relates toa new System andapparatus for introducing suitable grout into -contraction join-ts ofconcrete `structures in the course of their erection, or, preferablyafter t-heir completion, and to provide a direct method, of

forcing the grouting material into and along the contraction joints, andto avoid the attendant dilculties,uncertainties, vpoor quality of grout,and great expense caused by the use vof the present methods andavailable equipment.v

Concrete .contracts insetting and as it dries out and Icools oil itshrinks .to such eXtentt-hat large concrete structures will .developcracks that may :form at such positions and locations as to be dangerousto the stability of the structure. By locating contraction joints vinthe structure at frequent intervals and atproper positions -andlocations, .the development of dangerous cracks can be entirelyeliminated.. To .strengthen the concrete structure due to the weakeningeffect of the contraction joints, ythe contraction joints are lled withPortland cement grcut or other suitablecementing material, forced intoand along the contraction joint under pressure, preferably when thestructure isat its lowest temperature and when `the structure has 'thelleast external load to be carried by it. The Agrouting of the Vertical,normal contraction joints in concrete structures, such as retainingwalls and dams,- is very important, and-in such structures varched inplan and depending on vvarch action for fstability,-grouting of 'thevert-ical radialra'nd cir cumferential" joints is of "the greatest"importance; and it lis vadvisable to 'do vthe grou-ting at anlestimated pressure such'that when the-'maxi'- mum loads'are imposed onthestru'cture, there will be practically no tensil lstressesremaining-'inthe structure. In grouting thel contraction-joints of such.structures it is very important to pro-- vide means for the directremoval of Water,-for eign matter and the advancing sheet ofjgrout whichusually vgets 4so mixed with lforeign matter that it loses "itsstrength-and becomesof ajchalky weak character unsuitedfor binding thestructure together as a monolith. vBy 'providingmeans tov withdraw thisApoor .grade of 'grout from `all parts of the `joint and continuing to-force good grout into'the Vjoint until onlygoodgroutemerge's from the4joint vent system; insuresthat thejoiiit has only good grout in it overits entire area; This method of grouting of the contraction jointsbetween the various parts of such structures, cef ments the parts intoamonclithic s'tructure'whicn will .transmit 4archthrusts to the rockabutments on eachside of the canyon with lpractically no tensionstresses in the structure.

During the grouting of any contraction joint in the structure it is Veryimportant to force water into all joints not already grouted, and tomaintain the water in these joints at the con'- stant pressures at whichthey wi11 later `be grouted. Myinvention contemplates the use of anysystem'of voperative procedure 'in the accomplishmentof these resultsand any arrangement of open conduits attached to the face oftheconcrete. forming 'the contraction joint, and by any system of openconduits which provides means for forcing the cementing liuid in onegroup Iof open 4conduits to be designated the injection conduits', andwithdrawing or venting lthe fluid after it has passed into and throughthe contraction joint opening and on into and through another group ofopen conduits to be designated thevent conduits; the two groups solocated and so4 arranged as tol insure the forcingr in and retaining ofgood grout in all parts of the contraction joint. f

The .obj ects of Vmy nventionlare: First;- to provide l'an open conduitsystem and apparatus for Agrouting `the contraction joints which 'willoccur between different parts of a.

concrete structure of large dimensions such'as a massive concrete dam orretaining wall in which- 'one or more parts or units of the structureare ybuilt up progressively to partial or full height and allowed Vtoharden in advance of the other parts or units of the structure, whichare later poured against the formed faces of the partsor units firstbuilt.

Second; to provide an open conduit system and' apparatus for groutingconcrete structures where= by the'shrinkage and temperature openings orcracks designated `as contraction joints develop` ing between thedifferent parts or units of the structure, which have been poured atdifferent times, are grouted under pressure with cement grout andstrongly bonded-to form them vinto one integralwhol'e. Y Third; toprovide a simple, inexpensive, easily erected grouting system ofvsuiiciently rigid -construction to remain in placeV while theconcretestructure 'is being poured and will 'be' effective `in thoroughly llingthe opening in all contraction joints when the pressure groutingOperationis performed.

"Fourthj toprovide an open .conduit supplying, injecting', distributing,venting, grout system 'and apparatus 'can .beV progressively installedunit by unit as the forms for each successive vertical increment of alarge concrete unit are erected upon and above the concrete previouslypoured and hardened, and thereby avoiding any necessity of following anyspecial erection and construction programs from those which would befollowed were a grouting mechanism not used.

Fifth; to provide a plurality of open injection and venting conduitscommunicating independently between Apredetermined :positioned pointsinto the space to be grouted or 'filled and the outside source of supplywhere the grouting material is introduced under pressure, with saidplurality of communicating open conduits entirely embedded between theface of the concrete first poured and hardened, and the face of thesecond its connection to the vent riser conduit, the lower header pipeand its connection by T to the vent riser pipe and lap-joint.

Figures 1 and 7A are Side views of a structural concrete unit, Figure 'lrepresenting a typical grout panel at the bottom and Figure '1A atypical grout panel at the top of the structure, showing the injectionheader conduits I, the injection riser conduits 2, riser vent conduits3, injection pipe. connections', ventheader conduits 5, injecti'onris'erpipes 6. upper pipe header 1, vent riser pipes 8, lower pipe header 9,vent pipe connections Y I0 to the surface of the concrete, and groutstops II, the unit having the appearance it presents pour; thecorrugations of the vconcrete in the two concrete' units or parts of theconcrete strucjoint in the first pour protecting the injection andventing conduits from injury during the making of the second pour.

' Other objects and features ofadvantage'will be apparent during thecourse of thefollwing description.'

In the accompanying drawings" forming` 4part of this specificationandfin which like"'nu merals` are employed to designate likeparts'throu'ghout the same,

Figure 1 is a vertical sectional view, showi n'g 'a portion of theformed concrete face of thecontraction joint forming a unit or part ofthecon--4 crete structure,'inconne'ction with a grout supplying openheader conduit I, anopen ris'er conduit 2,v through both of which groutis forced into and along the contraction joint.

'Figure' 2 isa vertical sectional view of a portion of two finished andhardened concrete units, showing the contractionjoint'opening H betweenthe units, and the separated open header conduit and open riser conduitthrough which and out of which the grout can flow at all points alongthe open conduits into and alongv the contraction joint Figure 3 is ahorizontal sectional view of a portion of the finished and hardenedconcrete unit; showing the vopen riser'conduit 3 attachedto the formedconcrete faceof the rst pour'ed concrete.` *This View is typical of asection taken normal to the axis of the open conduits used in theinjection and venting conduits. Figure l is a side View of a portion ofa str,uc'` tural unit, showing a portion of the injection header-conduit I, injection riser condui t' '2, and pipe connection 1Ile'adingto the surface ofthe concrete passing to onefside o f groutstopj'I' This view inverted is also typical of the 'side' view of a ventheader conduit andfv'ent riser conduit and vent piper connection. f

Figure '5 is a horizontal sectional View of a portion ofY th'nished andhardened concrete unit, showing an injection header conduit I, Iand aninjection pipe 4 leading'to the surface. of the concrete passing tooneside of the grout stop I I; This View is'also typical of a horizontalsectional view of the vent header conduit and vent pipe leading to thesurface of the concrete.

Figure 6 is a vertical sectional vie'w of aport'ion of the finished andhardened concrete unit, showing an injection riser conduit 2an'ejectionriser pipe 6, and its connection to the open conduit I8, the upperheader pipe 1 and its connection by T-22 to the injection riser pipe 6,and a 11g inch fillet welded lap-joint 3U showing method of con#nectionat a reductionin size of angle conduits 2. Thi'sverticalsectional view inverted is also typical of the vent riser conduit, avent riser pipe and.

when ready for the pouring of an adjoining unit or 4part of the concretestructure.

Figures 8 and 9 are plan views of portions of ture showing the lowerportion of the grouting system installed and fastened in place after thefirst and lsecond units have hardened.

lFigure 10 is a plan view of a portion of one concrete unit -a a higherelevation than shown in Figures' 8 and '9, showing the open conduitsfastened to the concrete surface of one of the concrete units thatY hashardened.-

Figure 11 is a plan view of a portion of one'of the concrete units.,showing the typical configura.'- tion of one of the side faces thereofin the central portion of the unit; these configurations are suppressednear the horizontal grout stops.

Figures 12 and 12A are vertical sectional views ofa portion of thefinished and hardened concrete unit, Figure 12 representing a typicalsectional view of the bottomgrout panel or panels, and Figure 12A atypical sectional view of the top grout panel or4 panels'of thestructure, showing the injection header conduits I, injection riserconduits` 2, riser vent conduits 3, vent header conduit5,'injectionriser pipes 6, upper header pipe 1, vent-riser pipe 8, lowerheader pipes 9, and grout stops I I; these views also show the typicalcongurationjof one ofj the side faces of a concrete unit, withconfigurations suppressed near the horizontal grout stops. Figure 13 is-a horizontal sectional view of a fragment of a concrete-holding form,showing a metal strip secured to one side thereof which later closes thecontraction joint opening between two adjoining vconcrete units.

Figure V-14 isa horizontal sectional view of a portion of two hardenedunits and the joint-clos.. ing Y metal strip partially embedded therein.

Figure 15 is aplan view of fragments of two hardened units, showing' thecontraction joint opening between them andthe joint-closing strippartially embedded in each unit; and a plastic filler stripinserted inthe U of the joint-closing strip. Y

Referring now to vthe drawings, the apparatus I employ to accomplish theobjects of my inven-L tion, vconsists of an opengrout injection headerconduit I which is placed horizontally Vcrapproximately so, nearthelower confines or bottom edgeportion of each of the contractionjoints, bein g set preferably perauei thereto, and to this11ijectionheader conduitfL'I secure at predetermined distances apart;along its length, the lower ends of injection riser conduits 2, whichextend up vertically against yand attached tothe face of the concreteunit or block of concrete along whichthe contraction joint is to occurto the top surface'of the completed structure. In the pref'v ferre'dconstruction of the injection andv venting conduits', any suitable vopenconduits may be used',

the. header conduits are' preferably made .of` '2' inch by' Zivinch` by1/8 inichsmallsteel anglesandv the'v riser conduits are preferablyv madeoff'llly, inch by 11A inchby. 1inicio-.small steel angles in the lowerhalf ofthei riser, reducing in the upper halt of, the riser to l. inchby 1. inch by 1A; inch small steel angles and are made inanypredetermined length, the header and riser conduits communicate.through a suitable opening, preferably a triangular opening I2 inthe legof the header angles I and 5 respectively, Aand placing the bevel-cutendk of. the riser angles 2 and 3 respectively'over'the respective. outopenings, and. joiningtlre: two angles respectively by any suitablemeans that will. prevent the entry of mortar. at the joint, preferablyby 11e inch continuous fillet wells I3. ontheoutside.I surfaces ofcontact of the angles, the header and riser conduits held firmly againstthesmooth` surface III' of the previously poured and hardenedunit oftheiconcrete structure.

My 1 invention contemplates the securing of these header andriseranglesagainst the smooth surface I4 ofthe concrete by. any suitablemeans; but I preferablysecure them to the concrete face with. l0pennynails embedded in the previously poured concrete or similar suitableattachments substantially as shown in the accompanying drawings at; A.Ipreferably have the vertical riser angles made in a` number of unitswhose equalky lengths are each equal. to', or multiples of the verticaldepths of concretev to be poured. Theends. of two adjacent units beingjoined by any suitable means thatv willy prevent the' entry of mortar atthe joint, preferably by le inch continuous iillet welds. on` theoutside surfaces off contact of theangles. l

This unit method of; assembly and emplace ment is particularly Welladapted to structures. of the largest size andk also permits making thelengths of the units composing the riser angles such that,.ifthestructures wherein they are used be so great as to necessitateseveral successive pouringsv of concrete inl vertical sequence one abovethe. other, these lengths will either-.singly or in multiples equal the`amount that the con--v crete is raised in.these.progressivesteps/ofpourings required to reach the'nal completed height of the structure. Ihold.V the angles rmly against the smooth surface I 4'. of the concreteby any suitable means, preferably'by 'steel wire ties I5, the loopedends of whichv are placed over the bent nail ends A and wire tiestwistedA together over theheelof'theV angle by means of ay wire tying:brace',- or by twisting a` nail inserted inf the tie wire loops or othersuitable means which presses the angles rmly against the smooth surfaceI4 and makes a strong rigid con-- struction for the purpose intended,which can` be built up readily as fast as the `concrete is poured andhardened, and will remain Xed in the predeterminedly selected vanderected positions while the concrete is poured against the.

smooth surface I4 of the concrete unit and against the injection andventing lconduits attached' to the hardened` concrete surface I 4.

My invention also contemplates-the securing and' anchoring theseinjection and venting conduits to the concrete poured against the smoothsurface IIIv of the concrete' by any suitable means, preferably by steelstraps IS Whichare prefer-Y ably l inch wide by le inch thick'and 3inches long, attached to the steel angles at about 6 inch centers onalternate legs of the angles by any suitablemeans, preferably by 11ginch fillet weldsr IT'for- 1/2, inch along the-.Ledges cri the: straps:v

and theI joint opening-H widens, the: small steel angles arerigidlyrheldi to the concrete unit in.l Whichzthe anchorV straps I'6 areembedded', thev wire ties used are' much,l weaker and less rigidthanthek anchor' strapsi I6, thus. the wirey ties stretch, elongate andbreak,` and' ani opening occurs along/the edgesi of the angle-equal tothe opening Hof the joint, thus providing an opening for the groutftoo'w from theinj'ection` conduits, out, into, and along thejo'intopening, and out of, the jointropen-in'g and". into and along theAventconduits until. only-good grout remains in the joint openinglwh'enunder! fulll final' grout pressure.

My invention. alsocontemplates the making thep connections between theopen conduits andi the pipesby any suitablev meansthat 1 will" preventthe entry of mortar into the openv conduit or pipe attheir connections;I preferably use al1/8 inch plate I8 cut to t the outside dimensions ofthe section of the endothe conduit, usually cut on a bevel, andAattached thereto lby any suitable .v means, preferably 'by a le inchcontinuous Weld into the conduit or pipe, preferably by al le inchcontinuous WeldiZI atvthe outside surface of contact of the plateand thepipe. The riser pipes,-

preferably lqinch inediame'ter, are connected to the header pipes;preferably 1 inch indiameter chored- `to. the hardenedfconcrete forming.the

outer surfacev-ofithe corrugations by means or' nails embeddedliinlthefconcrete, and wire ties similar to the'method used in attaching theangle conduites to the concrete-surface I4;

In laying outa` unit of concrete, I preferablyform its-.borderoutlinealong its sides intoa continuous succession of equal corrugatio'ns 23`except near-the sloping surfaces' of the structure where the height isreduced to t in each panel boundedby groutfstops If-I the corrugations'being' formed' by projecting thecOncrete-Out, in, Aor at suitable anglesfrom the pla-ne surfacestrips I4, the width of thersmooth surface stripsI4 being made equal to the Width of` the at projecting arear23. Iembedsheet metal!J strips II,V calledy grout stops (except at the;upstream face where they are usually called water' stops), or othersuitable material having a U shaped fold IIA along the central portionof their widths, with their folded portion temporarily resting againstthe contraction jointforming faceof the form of the first pour ofconcrete, then after the form isremovedr the grout `stop is bent outinto its final position for embedment in` the second pour of` faces tothe exterior surface of the structure'forA its entire height.

'Ihe corrugations I4 and 23 inthe formed concrete units C and D ofFigures 8 and 9 that are' opposite to each other, forma continuoustongue and groove surface throughout practically' their length andheight' except where the corrugations are suppressed to facilitateforming and placing" the horizontal grout stops II; andiassumng that'the two units C and D have been poured and have hardened, then byclosing up the opposite ends F' andG ofthe space'E, thisspaceior unit Ecanbe poured and when itis poured the concrete flows into the verticalgroove members against the surfaces 23 and I4, that define the depth ofthese grooves; and this tongue andgroove vconstruction of new unitsbetween hardened units results in the new units being locked by thesenumerous tonguelike keys that enter the hardened units, against anymovements except the small vertical and horizontal movements due toshrinkage and temperature change; and after the concrete unit E has alsohardened, cooled, and the open joints H grouted, the new units arerigidly locked by these numerous tonguelike keys, against any possiblemovement whatever from pressures acting in a downstream direction thatare caused by the pressure of water or other material against itsupstream end, as the units in dam construction are placed transverselyacross the length of the dam, but the units can be arranged in any otherpredetermined positions relative to the length and breadth of otherkinds of concrete work.

After the concrete has been poured and has set, the forms are removed inthe usual manner, and the point ends of the embedded nails are now leftprotruding from the concrete.

I now bend the protruding ends 24 of the nails A over as indicated inFigure 3; I then place the grout injection and vent conduit and pipesystems and grout stops in position and secure them firmly in placeagainst the hardened face of the concrete units by means of wire ties asindicated in Fi-gure 3, and by fillet welding and threaded connectionsto connect the portions of these systems together. 'I'hese materials arepreferably installed in units equal to the depth of pour of the concretewith the upper ends of the conduits and pipes left protruding above thetop of the next lift or depth of concrete to be poured with the upperends temporarily plugged and capped to prevent them from becomingclogged during the pouring of concrete. Prior to the pouring of the nextlift of concrete above described the edges of the open conduits,preferably angles, are coated with cement mortar or other suitablematerial and let set to prevent the entrance of mortar into the conduitsduring they pouring and vibrating of the fresh concrete. After thepouring of the fresh concrete and prior to the time of the concretesinitial set the open conduits are flushed with water to Wash out anymortar that may have found its way into the conduits during the concretepouring operations.

, When the fresh concrete above described is first poured and whilestill in its workable senilliquid and plastic condition, it is inintimate contact with the contraction joint faces of the seasoned andhardened concrete on either side previously poured, but as it begins toset and harden, consider-able rise in temperature in the interior of themass occurs, and as the process of hardening and setting enters into itsfinal stages, this temperature becomes less and less, and in thickmasses of concrete, this heat of hydration of the cement is carried outof the mass by the circulation of cooling water and refrigerating waterthrough preferably one inch pices embedded in the concrete at the top ofeach 5 foot lift or pour of concrete with the pipes spaced at about 5foot centers horizontally, and the resulting drop in temperatureproduces a reduction or shrinkage in the mass of the concrete and itsphysical dimensions, thus causing its outer confines to contract towardsits center, and thoselportionsl originally in contact with the faces ofcontraction `ioints previously poured on, either side .recedesjor pulls.away from those faces, leavingy an opening Hl between them, and inasmuchas the open .conduits are rigidlyanchored by straps I6 in this newcontracting concretethey alsorecede or pull away from the faces of theconcrete units.

previously poured, so that. this receding movement produces twocontinuous lines of opening,

one along each leg of the :open conduit toy the. open space betweenthefaces ofthe concrete.4

When thisV receding movement between 'the open conduits ,and theconcrete face occurs,:it

is resisted only by the wireties I5 looped over the bent nails A, andthese wire ties I5v and. loops 25 are straightened, stretched andbroken.-

by the relative movement of, the two `units of concrete, as shown inFigure 2 toaccommodate this movement.

In Figures 1, 3, 4, 5, 7, 7A, a, 9, -10, 12 and 12A,

I illustrate a complete uid grout injectionand venting system set up andattached to a formed and hardened face of a contraction joint-and heldin place .by wire ties connected to bent over nails, the headand portionof the shank of which have been previously embeddedin .the concrete ofthe first pourwhich then hardened.

In Figure 2, I illustrate the condition after the A concrete of thethird pour has been placed..

against the hardened concrete face of the first pour, and the concreteofthe third pour has. hardened, cooled and shrunk away fromy thezhardened face of the rst pour of concrete, theny the open joint H isready to receive the grouting material between the two masses 4ofconcrete.

for filling the contraction joint opening H with cement grout. This isaccomplished by forcing and pumping the grout into the injection pipevthe edges of these conduits I. and 2 into andv along the opening H inthe contraction joint directly across the groovesld and the corrugations23, forcing the air, water, and foreignmatter in the open joint H aheadof the grout,

and to, into and along and down into the vent riser pipes 8 andthe lowerpipe header 9 and out of the open control valvevZIi until good grout ofproper consistency is discharged, whenthe control valve 26 is closed,land the additional grout pumped into the pipe I is forced along theopening H directly across vthe grooves I4 and the corrugations 23,forcing the air, water and foreign matter in the open joint H ahead ofthe grout, and to, into, and along the riser vent conduits 3 and thevent header conduit 5, ony

through the vent pipe connection I0, and out of the control valve 28until good grout of Vproper consistency isy discharged, when the controlvalve 28 is closed, and the required additional,`

pressure over the entire joint is appliedv and maintained by closing thecontrol valve 29, yor by a pressure control chamber or other suitablemeans, until the grout has hardened. .This

illustrates the grouting of the contraction joint if shown in Figure 8.In a similar manner vthe contraction joint shown in lFigurgfi is groutedWhen the entire concrete structure has. thus been completed, I haveincorporated in the structure and provided a direct communication.

2,341,518 and the grout let harden. When this process of grouting hasbeen continued over all the grout panels from bottom to top and fromdownstream face to upstream face of the dam, the concrete units ormasses of concrete are then integrally united into one monolithicstructure of concrete.

The same procedure of pumping grouting media of any suitable materialunder pressure into the bottom header conduits of each of the remainingjoints in turn until each system has been entirely nlled progressivelyfrom the bottom to the top, is followed until all the joints aregrouted. The work of grouting can be performed at any time after theconcrete has hardened upon both sides of the joint or joints, but thebest resuits are obtained when the concrete has a temperature belownormal and has attained maxirnum contraction as in winter or by coolingor refrigeration as herein described.

When using cement grout, I preferably force Water and air and watermixed under pressure through each space that forms the contraction jointopening H, washing out laitance and other deleterious materials thatprevent the bonding' of the grout to the concrete faces of the openjoint H. After the washing out of the joint,`I ll all the open joints Hfull of clear water for several days before starting to introduce thegrout, as this fills the interstices of the adjoining concrete withwater, and meistens all surfaces which the grout is required to bond,and insures that the grout will reach all portions of the voids in theopen joint with its proper free flowing consistency, which it would nototherwise retain were it progressively coming in contact with dryconcrete and losing its moisture content by absorption therein.

From the foregoing it will be observed that the filling or bondingmixture is introduced directly into the open joint along predeterminedlines progressively from the bottom of the structure towards the top,and the Venting of the open joint along predetermined lines parallel to,opposite to, between and above the grout injection lines, so that thebonding mixture must pass directly through and across the open jointbetween the injection and vent systems before it can be discharged outthrough the vent system, thus insuring free escape of the air upwardsand the water out of the joint from the ascendingbonding mixture,avoiding any possibility of entrapped or imprisoned air, gases, water,inert grout and laitance, or other poor quality bonding mixture, formingpockets or gaps where bonding could not otherwise occur; that theconduit system supplying the predetermined lines of entry into the jointand lines of vent out of the joint are directly in contact and open tothe joint opening along their entire lengths, on each side of the openconduits, thereby making certain the delivery of the bonding mixture toall parts of the joint surfaces to be bonded.

It is to be understood that the form of my invention herewith shown anddescribed is to be taken as a preferred example of the same, and

though it refers particularly to contraction joint openings as being thetype that are in a vertical plane, the invention can be equally used inany contraction joint in any other plane, including warped surfaces, andin any type of structure to which the principle of the invention can beapplied, and that variations relative to the material, size, shape andarrangement of the elements involved can be resorted to withoutdeparting from the spirit of the invention `orthe scope of the subjoinedclaims.

Having described my invention7 what I claim as new and desire to secureby Letters Patent is:

1. Apparatus for grouting the contraction jointl between two concreteunits, comprising open header and open riser conduits in a groutinjection system and a grout Venting system, the grout injectionconduits being in the form of a channel with the edges of the open sidethereof positioned against the contraction joint face of the firstpoured unit of hardened concrete, means yieldingly secured to saidconduits and to the contraction joint face of the first poured unit ofhardened concrete for enabling an opening to form between said edges andface by the shrinkage of the concrete whereby grout is permitted to flowinto the contraction joint, means associated with said conduits forfixing the same in the second poured unit of concrete, means connectingthe ends of said open conduits for the injection and venting of grout inthese open conduits, and means for closing the ends of the opencontraction joints.

2. The invention as set forth in claim 1, wherein the said meansconnecting the ends of said open conduits comprise injection and ventriser pipes connected to the ends of the open injection and vent riserconduits respectively and leading to an upper injection header pipe anda lower vent header pipe respectively and thence these header pipes leadto the surface of the finished concrete structure.

3. Apparatus for grouting the contraction joint between the two concreteunits, comprising means for closing the ends of the contraction joint, alower grout injection open header conduit and connected thereto aplurality of open grout injectionriser conduits and located opposite toand approximately half Way between and above these injection conduits,-a plurality of open grout Vent riser conduits and connected thereto anupper grout Vent open header conduit, means for flexibly holding theopen side of said conduits against; the smooth vface of the concreteunit first poured, pipe connections from said open header conduitsleading to the surface of the concrete structure and including aplurality of small pipes connecting rfom the upper ends of the groutinjection riser conduits to an upper header pipe that leads to thesurface of the concrete structure; and a plurality of small pipesconnecting from the lower ends of the grout vent riser conduits to alower header pipe that leads to the surface of the concrete structure.

RAY L. ALLDT.

